Ages and metallicities of five intermediate-age star clusters projected towards the Small Magellanic Cloud

Colour–magnitude diagrams are presented for the first time for L32, L38, K28 (L43), K44 (L68) and L116, which are clusters projected on to the outer parts of the Small Magellanic Cloud (SMC). The photometry was carried out in the Washington system C and T1 filters, allowing the determination of ages...

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Detalhes bibliográficos
Autores: Piatti, Andres E., Santos Junior, Joao Francisco Coelho dos, Claria Olmedo, Juan Jose, Bica, Eduardo Luiz Damiani, Sarajedini, Ata, Geisler, Doug
Formato: artículo
Estado:Versión publicada
Fecha de publicación:2001
País:Brasil
Recursos:Universidade Federal do Rio Grande do Sul (UFRGS)
Repositorio:Repositório Institucional da UFRGS
Idioma:inglés
OAI Identifier:oai:www.lume.ufrgs.br:10183/89970
Acesso em linha:http://hdl.handle.net/10183/89970
Access Level:acceso abierto
Palavra-chave:Fotometria astronômica
Aglomerados estelares globulares
Pequena Nuvem de Magalhães
Aglomerados estelares
Techniques: photometric
Magellanic clouds
Galaxies: star clusters
Descrição
Resumo:Colour–magnitude diagrams are presented for the first time for L32, L38, K28 (L43), K44 (L68) and L116, which are clusters projected on to the outer parts of the Small Magellanic Cloud (SMC). The photometry was carried out in the Washington system C and T1 filters, allowing the determination of ages by means of the magnitude difference between the red giant clump and the main-sequence turn-off, and metallicities from the red giant branch locus. The clusters have ages in the range 2–6 Gyr, and metallicities in the range -1.65 < ‰[Fe/HŠ] < -1.10, increasing the sample of intermediate-age clusters in the SMC. L116, the outermost cluster projected on to the SMC, is a foreground cluster, and somewhat closer to us than the Large Magellanic Cloud. Our results, combined with those for other clusters in the literature, show epochs of sudden chemical enrichment in the age–metallicity plane, which favour a bursting star formation history as opposed to a continuous one for the SMC.